docs(paper): add citation for NASA ESDS data metrics claim

Author: danielfromearth

paper/paper.bib

@@ -72,6 +72,14 @@ @misc{nasa_edl
   note = {Accessed: 2026-03-05}
 }
 
+@misc{nasa_esds_data_metrics,
+  title = {{ESDS} Data Metrics},
+  author = {{National Aeronautics and Space Administration}},
+  year = {2026},
+  url = {https://www.earthdata.nasa.gov/about/data-metrics},
+  note = {Accessed: 2026-03-31}
+}
+
 @misc{nasa_cmr,
   title = {{Common Metadata Repository (CMR})},
   author = {{National Aeronautics and Space Administration}},

paper/paper.md

@@ -121,14 +121,14 @@ either HTTPS download or direct S3 access when running in the Amazon Web Service
 `us-west-2` region -- where data within NASA's Earthdata Cloud reside. `earthaccess` also supports
 streaming data directly into analysis-ready formats using `fsspec` [@fsspec] and
 constructing virtual Zarr stores from archival formats (e.g., HDF5 and NetCDF4) using
-DMR++ metadata [@dmrpp], powered by VirtualiZarr [@virtualizarr] and kerchunk [@kerchunk], enabling drastic improvements in access performance. 
+DMR++ metadata [@dmrpp], powered by VirtualiZarr [@virtualizarr] and kerchunk [@kerchunk], enabling drastic improvements in access performance.
 
 
 # Statement of need
 
 NASA's Earth science data archive is one of the largest and most diverse collections of
-Earth observation data in the world, used by tens of thousands of researchers, educators,
-and decision-makers globally. However, the complexity of the underlying data infrastructure
+Earth observation data in the world, used by over ten million researchers, educators,
+and decision-makers globally [@nasa_esds_data_metrics]. However, the complexity of the underlying data infrastructure
 presents a significant barrier to scientific productivity. A typical data access workflow
 requires a researcher to: (1) authenticate with NASA Earthdata Login; (2) discover
 relevant datasets and granules through the CMR API; (3) parse metadata to obtain download
@@ -141,8 +141,8 @@ NASA's ongoing migration to the Earthdata Cloud adds further complexity, as rese
 must now contend with two possible access paradigms, traditional HTTPS downloads and S3-based
 access. These both may even occur within a single analysis workflow. During workshops organized by NASA
 Openscapes [@nasa_openscapes; @lowndes2019], the need for simpler tools became evident.
-`earthaccess` was created to address this gap: it provides uniform access to NASA
-Earthdata regardless of data storage location and handles authentication, credentials, and tokening behind the scenes, enabling researchers to focus more on scientific interpretation and discovery.
+`earthaccess` was created to address this gap: it provides uniform access to NASA
+Earthdata regardless of data storage location and handles authentication, credentials, and tokening behind the scenes, enabling researchers to focus more on scientific interpretation and discovery.
 The target audience includes Earth scientists, remote sensing researchers, climate modelers,
 hydrologists, ecologists, and any researcher, application developer, or educator who needs
 to work with NASA Earth science data. The library is designed to be approachable for those new to Python -- with a